Sivan W.

I build and rescue production AI products: agents, RAG and MCP tooling on Next.js, NestJS and Python. I cut a live SaaS's cloud bill from thousands a month to a few hundred. 12+ years shipping software that teams depend on. I built the first version of Bidalgo's SaaS, worked as a senior engineer at Forter and NICE, and was CTO at Time Tunnel before freelancing. WHAT I DO AI features and agents RAG and semantic search, assistants and copilots, multi-agent workflows with LangChain and LangGraph, tool calling, MCP, vector DBs (pgvector, Pinecone, Supabase), and human-in-the-loop flows. OpenAI, Claude, Gemini, and OpenRouter. SaaS platforms end to end Next.js and React. NestJS, Express, Laravel, or FastAPI. PostgreSQL and Supabase. Auth, Stripe billing, background jobs, real-time. Dashboards, portals, admin tools, marketplaces. Make + HubSpot / Monday when the product needs API↔CRM and ops automation. Extending and stabilizing live codebases Audits, bug fixes, careful refactors, performance and query work, migrations, and modernizing what already ships without a full rewrite when continuity is the goal. Deployment and infrastructure Docker, AWS, Vercel, Supabase, GitHub Actions CI/CD, monitoring, and cloud cost control. RECENT WORK Delet AI (live proptech SaaS, current client) Apartment self-tour and leasing automation for US property managers. Rebuilt the backend on NestJS, added AI agents designed so the platform isn't locked to one provider, and brought cloud spend down from thousands a month to a few hundred. Industry social network (pre-launch, NDA) NestJS backend, React Native app, Stripe subscriptions. Auth, feeds, and data model for a networking product with no template to copy. Stabilizing an existing SaaS Kept continuity on a live codebase: fixed critical production bugs, aligned architecture so features could ship safely, held a steady cadence, and simplified cloud deployment. Client recommendation is on the profile. HOW I WORK I treat the product as a business process: understand the clients and ops, map the flow, then implement and improve the architecture from there. Direct questions, honest estimates, clean PRs, and architecture another developer can pick up. Based in Israel (UTC+3). I work with US and EU founders and product owners. Message me with a short note about your product and what you want to change. You'll get specific questions and a realistic plan back, not a template.